Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

whining/whistle when driving

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by CAROLINAK5, Mar 14, 2002.

  1. CAROLINAK5

    CAROLINAK5 1/2 ton status

    Joined:
    Aug 2, 2001
    Posts:
    242
    Likes Received:
    0
    Location:
    lexington, north carolina
    when traveling at speeds over 25-30 mph, i get a whining/whistling noise whenever i let off the accelerator. as soon as i barely apply pressure to the gas pedal the noise goes away. (as far as i can tell since the road/engine noise is so loud). it does it every time until i get below 30 mph. i even coast from 40 mph to 30 mph and listen as the noise grows fainter and fainter as i near 30 mph. i can't get the noise to reproduce itself in the driveway, it only does it when traveling. i have tried spraying carb cleaner around the carb. while running at different rpm's in the garage, but can't find any gasket leaks.
    some help would be nice.
    350 sb......rochester carb.....th350 trans......goofy driver with nagging wife.
     
  2. denver75k5

    denver75k5 1/2 ton status

    Joined:
    May 15, 2001
    Posts:
    1,017
    Likes Received:
    0
    Location:
    Somewhere In The Woods
    Sounds like a Vacum leak to me, check the vacum line going down to the tranny, if thats not it check the rest of your vacum lines leading from the carb and manifold.
     
  3. Zeus33rd

    Zeus33rd Smarter than you GMOTM Winner

    Joined:
    Mar 14, 2002
    Posts:
    7,324
    Likes Received:
    9
    Location:
    Grass Valley, CA
    Maybe a speedo cable in need of lubrication/replacement?
     
  4. EDdaTREE

    EDdaTREE 1/2 ton status

    Joined:
    Feb 18, 2000
    Posts:
    1,253
    Likes Received:
    0
    Location:
    Austintown, OHIO
    Vacuum leaks will drive you nuts...start thinking in the dumbest, most oddball ways, and start chasing loose bolts, old rubber lines, slipping belts, bad bearings, alternators, etc.
     
  5. Snowbound

    Snowbound Registered Member

    Joined:
    Mar 12, 2002
    Posts:
    52
    Likes Received:
    0
    Location:
    Minot N.D.
    I get the same whine at idle. Haven't been able to find it. Let me know what you find. The last time I was able to drive it was November. Wife dosen't drive it much now. I will be able to work on it in 3 weeks.
     
  6. ChevyCaGal

    ChevyCaGal 3/4 ton status

    Joined:
    Dec 16, 2000
    Posts:
    8,158
    Likes Received:
    0
    Location:
    Sacramento, CA USA
    I doubt this is it... but I had stereo goblins once (whine in the alternator)... anytime I gassed it they showed up. Took me forever to figure it out!
     
  7. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

    Joined:
    Mar 5, 2001
    Posts:
    15,684
    Likes Received:
    1,392
    Location:
    642 Days to BB2018
    Carolina,

    I had the same exact problem on mine. Any time I released the gas it would "whistle" and the whole time it was coasting down it would whistle until it got to maybe 1000RPM or less.

    My mechanic suggested that it could just be a result of the amount of vaccuum the engine is pulling and the position of the throttle plates in the carb.....as the air passes over those plates at just the right speed you get the whistling sound.

    I tried a LOT of other ideas.....PCV valve, vaccuum leaks, loose bolts, etc. The whole process of swapping to my new Q-Jet fixed it for me, but I have a feeling you might be able to slightly alter the position of those throttle plates during "coasting" to prevent the whistle.

    Of course, you should check the obvious stuff first. But I thought I'd share this rather unusual observation in case none of that other stuff works. It's embarrassing to drive a "whistle-truck" around!!! /forums/images/icons/laugh.gif
     
  8. CAROLINAK5

    CAROLINAK5 1/2 ton status

    Joined:
    Aug 2, 2001
    Posts:
    242
    Likes Received:
    0
    Location:
    lexington, north carolina
    coming from a "man in green" oughta be gold!!! (just raggin' ya )
    i'll give it a try, as well as checking out my vacuum lines. i figured it has to have something to do with air flow seein' as how it only does it while driving. i rebuilt this carb about 6 months ago but have only noticed this problem over the past few weeks. odd thing is that the other day i drove it over 100 miles round trip and never heard a thing. then i go on another road trip and it starts back up again.
    and i'll agree...if there is going to be any whistling going on in the blazer, it will come from the driver!
    thanks for the suggestions. i'll keep ya updated.
     
  9. FatBoyBlazer

    FatBoyBlazer 1/2 ton status

    Joined:
    Feb 22, 2001
    Posts:
    1,508
    Likes Received:
    0
    Location:
    Worcester, MA
    how do you get rid of "stereo goblins"
     
  10. NoSmog73

    NoSmog73 1/2 ton status

    Joined:
    Sep 28, 2001
    Posts:
    2,348
    Likes Received:
    0
    Location:
    lodi,ca
    get a better gound... Sorry to be so short.If you have an amp or amps get them to a better ground.If you just have a radio then you could move that one too but as a last resort? If that doesn't work then move your battery ground to the frame and get a wider or better ground strap that goes to the firewall..Many of the stereo's whining come from a bad ground.I also think there are plug wires that help with the radio whining but of the top of my head don't remember which one's they are...
     
  11. newyorkin

    newyorkin 1 ton status

    Joined:
    May 8, 2001
    Posts:
    16,555
    Likes Received:
    157
    Location:
    Los Estados Unitos
    Noise filters over the power lines help too, if there're a lot of high amperage lines nearby. I'm rewiring a lot of stuff to bring some heavy amperage into the console. My amp currently whistles because I have it so close to another high amp line... Gotta get off my arse and move that stuff around one of these days...
     
  12. NoSmog73

    NoSmog73 1/2 ton status

    Joined:
    Sep 28, 2001
    Posts:
    2,348
    Likes Received:
    0
    Location:
    lodi,ca
    Sorry for the off org.post.
    Ya also keep your RCA cables and the main power wires on diferent sides (like maybe run them down each side of the tranny hump)
     

Share This Page